Method and device for pulling a cable through a section of pipe

ABSTRACT

An improved cable pulling device and method is shown. The cable pulling device is smaller, less expensive, and easy to use for lateral line replacement. The cable pulling device includes a cable contacting portion that provides supplemental frictional force during a rotational pulling stroke. Among other advantages, this allows a smaller, more compact design that provides higher gripping and pulling power. Embodiments as described above further allow for a smooth jaw configuration that reduces cable damage. A cable pulling device is also shown that includes a configuration of a force distributing device. One embodiment includes substantially orthogonal plates that help to reduce device twisting during a pulling operation. In a further embodiment, a force distributing device is adapted for attachment to a ground working implement arm.

This application is a continuation of U.S. patent application Ser. No.10/942,411, filed Sep. 16, 2004, which is a continuation of U.S. patentapplication Ser. No. 10/341,549, filed Jan. 13, 2003, which claimspriority to U.S. Provisional Application No. 60/359,954, filed Feb. 27,2002 and U.S. Provisional Application No. 60/347,544, filed Jan. 11,2002, all of which are incorporated herein by reference.

TECHNICAL FIELD

The invention relates to pulling cables through sections of pipe.Specifically, the invention relates to pipe bursting and replacement orpipe lining.

BACKGROUND

Pipe such as cast iron, clay or ductile metal pipe has been used forconnecting homes and creating networks for utilities such as water,sewer, or gas, etc. As the pipe becomes old, it may crack or break,necessitating replacement of the pipe.

A technique know as pipe bursting is currently used as a convenientmethod to replace underground pipe without the need to dig up the pipeto be replaced. A pipe breaking device, commonly called an expander or amole, is pulled or pushed through the existing pipe while it is stillunderground. The expander is designed to break, or burst the pipe, andat the same time to expand the broken pieces of the pipe into thesurrounding soil. The expansion of the broken pipe allows the expanderto pull a replacement pipe into place. Alternatively, some methods usethe expander to merely pull a smaller diameter pipe into place insidethe existing pipe, however, this method restricts the flow in thereplaced pipe due to the smaller diameter of the replacement or linerpipe. The pipe bursting, or lining technique has typically been employedon large diameter pipe such as water or sewer main lines. Due to thesize of pipe in these types of replacements, the equipment used forpulling or pushing the expander through the pipe requires a great dealof force. As a result, common equipment in the industry for pulling orpushing the expander is relatively large and expensive such as an aboveground winch and pulley system. These larger scale methods also commonlyrequire a large access pit to be excavated on at least one end of thepipe to be replaced.

More recently, the technique of pipe bursting has been employed forsmaller diameter pipe such as for lateral lines. Smaller branch pipesfrom a large water or sewer, etc. main line are commonly referred to aslateral lines. Replacement of smaller lateral lines is typically a lowercost job than main lines, and due to the lower profit possibilities,these jobs are frequently left to smaller contractors.

A problem arises for the smaller contractors who wish to use the pipebursting technique for lateral line replacement. The common industryequipment for drawing or pushing the expanders through the pipe is tooexpensive to purchase or lease relative to the smaller profits fromlateral line replacement.

What is needed is a cable pulling device that is smaller, lessexpensive, and easy to use to be practical for lateral line replacement.

SUMMARY

The above mentioned needs of smaller, less expensive and easier to usecable pullers are addressed by the present invention and will beunderstood by reading and studying the following specification.

A cable pulling device is shown. The cable pulling device includes abase unit, and a cable contacting portion. A pivot joint rotatablyconnects the cable contacting portion to the base unit. The cablepulling device also includes a first cable gripping device attached tothe cable contacting portion, the first cable gripping device beingadapted to selectively engage and release a cable. The cable pullingdevice also includes an actuating device adapted to cycle the cablecontacting portion back and forth about the pivot joint.

Another embodiment of a cable pulling device is shown. The cable pullingdevice includes a base unit and a cable contacting portion. A pivotjoint rotatably connects the cable contacting portion to the base unit.The cable pulling device also includes a first cable gripping deviceattached to the cable contacting portion, the first cable grippingdevice being adapted to selectively engage and release a cable. Thecable pulling device also includes an actuating device adapted to cyclethe cable contacting portion back and forth about the pivot joint. Thecable pulling device also includes a connection surface attached to thecable pulling device, wherein the connection surface is adapted tocouple to a ground working implement arm. Another embodiment of a cablepulling device is shown. The cable pulling device includes a base unitand an arcuate cable guide. The arcuate cable guide includes a cableguide groove and a friction engaging surface substantially within thecable guide groove. The cable pulling device also includes a pivot jointrotatably connecting the arcuate cable guide to the base unit and afirst cable gripping device attached to the arcuate cable guide adjacentto the friction engaging surface. The cable pulling device also includesa first actuating cylinder attached to the first cable gripping device,wherein the first actuating cylinder is adapted to actuate a grippingforce between the first cable gripping device and the friction engagingsurface; and a second actuating cylinder adapted to cycle the arcuatecable guide back and forth about the pivot joint.

A method of pulling a cable through a section of pipe is also shown. Themethod includes placing a cable within a section of pipe, and placing aportion of the cable outside the section of pipe along a frictionengaging surface of a cable contacting portion. The method furtherincludes cycling the cable contacting portion through at least onecycle. A cycle includes actuating a first cable gripping device attachedto the cable contacting portion , wherein a gripping force is applied tothe cable in at least a portion of the friction engaging surface. Thecycle also includes pivoting the cable contacting portion about a pivotjoint from a first end of a range of motion to a second end of the rangeof motion to generate an axial pulling force in the cable. The cyclealso includes releasing the first cable gripping device at the secondend of the range of motion to release the gripping force on the cable,and returning the cable guide to the first end of the range of motion.

These and other embodiments, aspects, advantages, and features of thepresent invention will be set forth in part in the description whichfollows, and in part will become apparent to those skilled in the art byreference to the following description of the invention and referenceddrawings or by practice of the invention. The aspects, advantages, andfeatures of the invention are realized and attained by means of theinstrumentalities, procedures, and combinations particularly pointed outin the appended claims.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 shows a perspective view of a cable pulling device according toone embodiment of the invention.

FIG. 2A shows an exploded view of a cable pulling device according toone embodiment of the invention.

FIG. 2B shows a component of a cable pulling device according to oneembodiment of the invention.

FIG. 2C shows a cross section from FIG. 2B.

FIG. 2D shows jaw components of a cable pulling device according to oneembodiment of the invention.

FIG. 2E shows other jaw components of a cable pulling device accordingto one embodiment of the invention.

FIG. 3 shows a perspective view of a cable pulling device a according toone embodiment of the invention

FIG. 4A shows a perspective view of a cable pulling device according toone embodiment of the invention.

FIG. 4B shows a perspective view of a cable pulling device according toone embodiment of the invention.

FIG. 5 shows a flow diagram of a method according to one embodiment ofthe invention.

DETAILED DESCRIPTION

In the following detailed description of the invention, reference ismade to the accompanying drawings which form a part hereof, and in whichis shown, by way of illustration, specific embodiments in which theinvention may be practiced. In the drawings, like numerals describesubstantially similar components throughout the several views. Theseembodiments are described in sufficient detail to enable those skilledin the art to practice the invention. Other embodiments may be utilizedand structural, or operational changes may be made without departingfrom the scope of the present invention.

In the following description, the term cable refers to any of a numberof flexible products. The term cable includes wire rope, and cables orropes made from a number of materials including steel. In the followingdescription, unless otherwise provided, descriptions of forces,locations, etc. that involve a cable as described above will refer toradial and axial forces. Axial forces, such as tension in a cable referto forces substantially along a longitudinal axis of a cable. Forcessuch as gripping forces generally refer to forces that resist acountering axial force. In one example, a gripping force includes africtional force generated by an element such as a jaw, placed incontact with a cable. A frictional force is related to a radial forcesubstantially normal to the longitudinal axis of a cable, the surfacearea of contact, and a coefficient of friction related to the materialinterface.

FIG. 1 shows a cable pulling device 100. The cable pulling device 100includes a base unit 110 and a cable contacting portion 120. The cablecontacting portion 120 is coupled to the base unit 110 at a pivot joint102. The cable contacting portion 120 is rotatable in a range of motion104 relative to the base unit 110 about the pivot joint 102. In oneembodiment, a main actuator 130 is coupled between the base unit 110 andthe cable contacting portion 120 to drive the cable contacting portion120 in the range of motion 104. In one embodiment, a first cablegripping device 170 is coupled to the cable contacting portion 120. Thefirst cable gripping device 170 is used to apply a gripping force to acable 140. In one embodiment, the first cable gripping device 170applies a gripping force by actuating at least one jaw against the cablecontacting portion 120. Further embodiments of the first cable grippingdevice 170 are discussed in detail below.

In one embodiment, a second cable gripping device 180 is furtherincluded in the cable pulling device 100. In one embodiment, the secondcable gripping device 180 is designed to selectively apply a cablegripping force. In one embodiment the second cable gripping device 180provides a cable gripping force at least during periods of operationwhen the first cable gripping device 170 is disengaged from the cable140. Further embodiments of the second cable gripping device 180 arealso discussed in detail below.

FIG. 2A shows an embodiment of a cable pulling device 200. A base unit210 is shown, with a cable contacting portion 220. The cable contactingportion 220 is coupled to the base unit 210 via a pivot joint 212. Inone embodiment, the pivot joint 210 is removable using quick releasepins 222.

A first cable gripping device 270 is also shown in FIG. 2A. In oneembodiment, the first cable gripping device 270 includes a pair of sideplates 252, a cam 264, a jaw carrier 256, a first jaw 260 and a secondjaw 262, and a first cable gripping device actuator 250. The first jaw260 is coupled to the jaw carrier 256, while the second jaw 262 iscoupled to the cable contacting portion 120. The jaw carrier 256 isfurther coupled to the side plates 252, and the side plates 252 arecoupled to the cam 264.

The cam 264 is rotatable through a range of motion that facilitatesactuation of the first cable gripping device 270. The side plates 252are coupled to the cam 264, such that when the cam 264 is rotatedthrough the range of motion, the side plates 252 are forced towards thecable contacting portion 220 in a clamping motion. The cam 264 isactuated in its range of motion by the first cable gripping deviceactuator 250. In one embodiment, the actuator 250 is coupled between thecam 264 and the cable contacting portion 220.

Other methods for actuating the first cable gripping device 270 arecontemplated within the scope of the invention. While a cam 264 andactuator 250 are shown in FIG. 2A, alternative mechanical linkages orforce generating devices can be used. In one embodiment, the first cablegripping device 270 is selectively actuated by an actuator 250 asdescribed above. Other embodiments include a first cable gripping device270 that is passively actuated, such as by cable tension. In oneembodiment, the first cable gripping device 270 includes, but is notlimited to, a wedge, a camming device, a number of collets, etc.

In one embodiment, a second cable gripping device 280 is furtherincluded. FIG. 2A shows one embodiment of the second cable grippingdevice 280 including a pair of jaws 282. Embodiments with a single jaw,or multiple jaws are also contemplated within the scope of theinvention. Further, aside from use of jaws, alternative mechanicallinkages or force generating devices can be used. In one embodiment, thepair of jaws 282 are coupled to the base unit 210 using a pair of pivotjoints. In one embodiment, the pair of jaws 282 are actuated to apply acable gripping force in a passive manner. In one embodiment, the pair ofjaws 282 are actuated in response to an axial cable tension using acamming or wedging action. Other embodiments include a second cablegripping device 280 that is selectively actuated by an actuation device.

In one embodiment, a jaw opening device 284 is further included andcoupled to the pair of jaws 282. In operation, a user is optionallypermitted to open the pair of jaws 282 using the jaw opening device 284for reasons such as to insert a cable 240 into the second cable grippingdevice 280 in an initial setup for a cable pulling operation. Notably,the pair of jaws 282 in FIG. 2A are positioned such that when open, theypermit the cable 240 to be inserted from above, or below withoutdisassembly of the second cable gripping device 280. This configurationallows a user to quickly and efficiently insert a cable in an initialsetup operation. In one embodiment, the jaw opening device 284 furtherserves a function as a jaw synchronizing device. Elements such asmeshing teeth serve to move both of the pair of jaws 282 in asubstantially symmetric manner.

In one embodiment, the cable pulling device includes a main actuator 230that drives rotation of the cable contacting surface 220 about the pivotjoint 212. As discussed above, in one embodiment, the first cablegripping device 270 also includes an actuator 250 that provides forcefor a gripping operation of the first cable gripping device 270.Although two separate actuators are shown in FIG. 2A, other embodimentsinclude a single actuator that provides both main rotation force, and agripping force. In one embodiment, the main actuator 230 and theactuator 250 include hydraulic cylinders. Other possible actuatorsinclude, but are not limited to, electric actuators, pneumaticactuators, etc. In one embodiment, the main actuator 230 and theactuator 250 of the first cable gripping device are coupled separatelyto an external source of hydraulic pressure. In one embodiment, the mainactuator 230 and the actuator 250 of the first cable gripping device arecoupled to a single external source of hydraulic pressure, and actuatedin a desired sequence using a timing valve. Although the embodimentshown in FIG. 2A is adapted for an external hydraulic pressure source,other embodiments include local hydraulic pressure sources, or othersources of actuation power.

FIGS. 2B and 2C further show the cable contacting portion 220. The cablecontacting portion 220 shown in FIG. 2B includes a joint portion 224that is used to rotatably join the cable contacting portion 220 with thebase unit 210 as shown in FIG. 2A. FIG. 2B further shows an actuatormount 232 for coupling to the main actuator 230 as shown in FIG. 2A. Inone embodiment, a cable gripping device actuator mount 228 is included,along with a cam engaging surface 226. The cable gripping deviceactuator mount 228 and cam engaging surface 226 are used in embodimentsdescribed above that incorporate a cam 264 and an actuator 250 with thefirst cable gripping device 270. In one embodiment, a jaw engagingregion 258 is further included in the cable contacting portion 220 toaccept at least one jaw.

In one embodiment, the cable contacting portion 220 includes a cableguide surface 221. In one embodiment, the cable guide surface includesan arcuate portion 227. The arcuate portion 227 may include an arc of acircle, a portion of an ellipse, or another curved segment such as anexponential, or logarithmic curve. A cable is both guided by the cableguide surface 221, and frictionally engaged by the cable guide surface221. Frictional engagement is made possible due to the rotation of thecable contacting portion 220, in contrast to a linear pull arrangement.During rotation, an axial force of the cable also provides a normalforce of the cable against the cable contacting portion 220. Thespecific shape of the cable contacting portion 220 (such as an arcuateshape) helps to determine the magnitude and rate of change of normalforces generated against the cable contacting portion 220. This normalforce contributes to frictional engagement of the cable with the cablecontacting portion 220. In a linear pull arrangement, no normal force isgenerated.

In one embodiment, the cable guide surface 221 includes a groove with adimension 225 that is sized to be smaller than a cable that is to bepulled. In one embodiment, the groove includes at least one tapered wall223 that further fictionally engages a cable to be pulled.

As discussed above in one embodiment, the first cable gripping deviceincludes a number of jaws. FIG. 2D illustrates an example of jawsassociated with one embodiment of the first cable gripping device 270.The first jaw 260 and the second jaw 262 are shown in FIG. 2D. In oneembodiment, the jaws are fabricated separately from other components tofacilitate replacement or repair of jaws. Other embodiments include jawsthat are integrally formed into components of the cable pulling device200. One embodiment of the second jaw 262 includes a protrusion 263 usedto engage the pair of side plates 252 as shown in FIG. 2A. In oneembodiment, the first jaw 260 and the second jaw 262 include a smoothcable contacting surface 261 and 265 respectively. Other embodimentsinclude a textured cable contacting surface 261, such as ridges, orteeth. In one embodiment, only one of the jaws includes a smooth cablecontacting surface. While a textured cable contacting surface 261enhances a gripping force, a smooth cable contacting surface 261 isdesirable because in minimizes damage to a surface of a cable.

A smooth cable contacting surface 261 of a jaw is practical inapplications where a high enough gripping force is provided, without theneed for a textured jaw surface. One advantage of utilizing a cablecontacting portion 220 as described above with features thatfrictionally engage a cable is that the cable contacting portion 220provides supplemental force to resist cable tension during a cablepulling operation. In some applications, a smooth cable contactingsurface 261 of a jaw is only possible in designs were a supplementalforce is provided, such as the force provided by embodiments of thecable contacting portion 220 as described above.

FIG. 2E illustrates one example of a jaw 282 as shown in FIG. 2A asincluded in the second cable gripping device 280. A pivot feature 285such as a circular hole is shown in the jaw 282. Similar to embodimentsof jaws used in the first cable gripping device 270, in one embodiment,the jaw 282 includes a smooth cable contacting surface 283. Otherembodiments include a textured cable contacting surface 261, such asridges, or teeth.

FIG. 3 shows a cable pulling device 300. The cable pulling device 300includes a first load spreading portion 310 and a second load spreadingportion 320. In one embodiment, the first load spreading portion 310 andthe second load spreading portion 320 include substantially flat plates.Materials such as aluminum, steel, other metals, composite materials,etc. are acceptable materials for formation of the first load spreadingportion 310 and the second load spreading portion 320. In oneembodiment, the first load spreading portion 310 and the second loadspreading portion 320 are substantially orthogonal to each other. In oneembodiment, the first load spreading portion 310 includes at least onehandle 322. In one embodiment, the second load spreading portion 320includes at least one handle 312. One function of handles includesoperator convenience in carrying the respective load spreading portions.In one embodiment, the first load spreading portion 310 and the secondload spreading portion 320 are separately detachable from the cablepulling device 300. Connecting features such as feature 302 are includedin one embodiment to allow for easy coupling and uncoupling of the loadspreading portions 310 and 320 from the cable pulling device 300.Examples of connecting features 302 include, but are not limited tobolts, dovetail joints, pins, slots, etc.

In operation, the first load spreading portion 310 and the second loadspreading portion 320 of the cable pulling device 300 serve as forcedistributing surfaces. Each of the portions 310, 320 act on an earthsurface in a different direction normal to a main surface of therespective plates. In one embodiment, the first load spreading portion310 acts on a wall of a pit, the wall being substantially normal to adirection of cable pulling. In one embodiment, the second load spreadingportion 320 acts on a bottom surface of a pit, the bottom surface beingsubstantially parallel with the ground. The two force distributingdirections provided by the first load spreading portion 310 and thesecond load spreading portion 320 provide a more stable pulling platformfor the cable pulling device 300. In one embodiment, the first loadspreading portion 310 and the second load spreading portion 320 togethercombine force distributing forces to resist a downward twisting force.

FIG. 4A shows a cable pulling device 400. The cable pulling device 400includes a puller 401, and a force distributing device 410. In oneembodiment, the puller is similar to embodiments described above. In oneembodiment, the force distributing device 410 is easily detachable fromthe puller 401. Connecting features such as feature 402 and matingfeature 412 are included in one embodiment to allow for easy couplingand uncoupling of the force distributing device 410 from the cablepulling device 400. Examples of connecting features 402 and matingfeatures 412 include, but are not limited to bolts, dovetail joints,pins, slots, etc.

In one embodiment, the force distributing device 410 includes a firstload spreading portion 414 and a second load spreading portion 416. Inone embodiment, the first load spreading portion 414 and the second loadspreading portion 416 include substantially flat plates. Materials suchas aluminum, steel, other metals, composite materials, etc. areacceptable materials for formation of the first load spreading portion414 and the second load spreading portion 416. In one embodiment, thefirst load spreading portion 310 and the second load spreading portion320 are substantially orthogonal to each other. FIG. 4A further shows anopening 422 that allows for convenient loading of a cable (not shown)into the puller 401 without the need to disassemble any components ofthe cable pulling device 400.

The force distributing device 410 shown in FIG. 4 illustrates anembodiment where the first load spreading portion 414 and the secondload spreading portion 416 are attached together to form an integral,one piece component. In one embodiment components of the forcedistributing device 410, including the first load spreading portion 310and the second load spreading portion 320 are welded together.

The force distributing device 410 further includes a connection surface418. In one embodiment, the connection surface 418 further includes atleast one connection feature 420. In one embodiment, the connectionfeature 420 includes a number of threaded holes to accept bolts. Otherconnection features 420 include slots, pins, quick connect linkages,etc.

FIG. 4B further illustrates the cable pulling device 400 coupled to animplement arm 430. FIG. 4B illustrates the implement arm 430 attached tothe connection surface 418 of the force distributing device 410. Otherembodiments include coupling of the implement arm 430 directly to thepuller 401 of the cable pulling device 400. Ground working implementsthat may include an implement arm 430 include, but are not limited to,an excavator, back hoe, skid steer vehicle, etc. Attachment of the forcedistributing device 410 to an implement arm 430 makes location of thecable pulling device 400 in a location such as a pit easier and safer.Ground working implements also frequently have auxiliary hydraulicsystems that may be used to power the cable pulling device 400.

FIG. 5 illustrates one method of operation of a cable pulling deviceaccording to embodiments described above. A cable pulling device isattached to a cable, that has been inserted through a pipe to bereplaced. In one method, the cable is further attached to a burstinghead, or expander, etc. that is to be pulled through the pipe to bereplaced. The expander draws a new pipe into place as it is drawnthrough the old pipe. Among other options, the pipe to be replaced canbe burst by the expander, or the bursting head can be used to draw asmaller diameter liner into the pipe to be replaced.

Using an embodiment of a cable pulling device as described above, thecable is placed into a first cable gripping device and a second cablegripping device. The cable pulling device is then cycled through anumber of cycles until the cable is pulled to a desired distance. In oneembodiment, a cycle includes first actuating the first cable grippingdevice to clamp an end of the cable against a cable contacting portion.The cable contacting portion is then rotated about a pivot joint from afirst end to a second end of a range of motion. Rotation, in contrast toa linear pulling mechanism, allows the cable contacting portion toprovide a supplemental frictional force that aids in cable gripping. Asdiscussed above, the supplemental frictional force provided by the cablecontacting portion both enhances the gripping force, and allows smoothjaws to be utilized, thus reducing cable damage.

At the second end of the range of motion, the first cable grippingdevice is released and the second cable gripping device is actuated. Thesecond cable gripping device holds the cable in place while the cablecontacting portion returns to the first end of the range of motion. Oncethe cable contacting portion returns to the first end of the range ofmotion, the cycle can be repeated as many times as necessary to pull thecable to the desired distance.

CONCLUSION

Thus has been shown a cable pulling device and methods where the cablepulling device is smaller, less expensive, and easy to use for lateralline replacement. The cable pulling device includes a cable contactingportion that provides supplemental frictional force during a rotationalpulling stroke. Among other advantages, this allows a smaller, morecompact design that provides higher gripping and pulling power.Embodiments as described above further allow for a smooth jawconfiguration that reduces cable damage.

A cable pulling device has also been shown that includes a configurationof a force distributing device. One embodiment includes substantiallyorthogonal plates that help to reduce device twisting during a pullingoperation. In a further embodiment, a force distributing device isadapted for attachment to a ground working implement arm. Thisconfiguration, is safer and easier to operate because it removes theneed to lift the cable pulling device into an excavated pit, and itsubstantially keeps the operators out of the pit, where they are at anincreased risk of injury.

Although specific embodiments have been illustrated and describedherein, it will be appreciated by those of ordinary skill in the artthat any arrangement which is calculated to achieve the same purpose maybe substituted for the specific embodiment shown. This application isintended to cover any adaptations or variations of the presentinvention. It is to be understood that the above description is intendedto be illustrative, and not restrictive. Combinations of the aboveembodiments, and other embodiments will be apparent to those of skill inthe art upon reviewing the above description. The scope of the inventionincludes any other applications in which the above structures andfabrication methods are used.

1. A cable pulling device, comprising: a frame; a cable contactingportion movably coupled to the frame for movement in a non-linear rangeof motion; a first cable gripping device coupled to the cable contactingportion to selectively engage and release a cable; a second cablegripping device coupled to the frame to selectively engage and releasethe cable; and at least one actuator to move the cable contactingportion in the non-linear range of motion and to actuate at least one ofthe first and second cable gripping devices.
 2. The cable pulling deviceof claim 1, wherein the second cable gripping device provides a cablegripping force at least during periods of operation of the cable pullingdevice when the first cable gripping device releases the cable.
 3. Thecable pulling device of claim 1, wherein the at least one actuator is amain actuator coupled between the frame and the cable contactingportion.
 4. The cable pulling device of claim 3, wherein the mainactuator moves the cable contacting portion in the non-linear range ofmotion and actuates the second cable gripping device.
 5. The cablepulling device of claim 4, further comprising a gripping actuatorengaged to the cable contacting portion for actuating the first cablegripping device.
 6. The cable pulling device of claim 5, wherein thegripping actuator is coupled between the cable contacting portion and acam, the cam being operatively connected to the first cable grippingdevice, wherein rotation of the cam actuates the first cable grippingdevice.
 7. The cable pulling device of claim 1, further comprising afirst load spreading plate coupled to the frame to spread a portion of apulling load against a first surface.
 8. The cable pulling device ofclaim 7, further comprising a second load spreading plate coupled to theframe to spread a portion of a pulling load against a second surface. 9.The cable pulling device of claim 8, wherein the first and second loadspreading plates are oriented generally perpendicularly to one another,the first surface being a side of a pit and the second surface being abottom surface of a pit, wherein the first and second load spreadingplates act on the side and bottom surface of the pit, respectively, toresist a downward twisting force.
 10. The cable pulling device of claim1, wherein the cable contacting portion includes an arcuate portion. 11.The cable pulling device of claim 10, wherein the arcuate portion of thecable contacting portion cyclically frictionally engages the cableduring movement of the cable contacting portion through the non-linearrange of motion.
 12. The cable pulling device of claim 10, wherein thearcuate portion includes variations in radius.
 13. The cable pullingdevice of claim 12, wherein the arcuate portion is elliptical.
 14. Thecable pulling device of claim 1, wherein the at least one actuator is ahydraulic cylinder.
 15. The cable pulling device of claim 1, furthercomprising a connection surface for selective engagement with animplement arm.
 16. A cable pulling device, comprising: a frame; a cablecontacting portion movably coupled to the frame for movement in anon-linear range of motion, the cable contacting portion including anarcuate portion for cyclically frictionally engaging the cable duringmovement of the cable contacting portion through the non-linear range ofmotion, the arcuate portion having variations in radius; a first cablegripping device coupled to the cable contacting portion to selectivelyengage and release a cable, the first cable gripping device including afirst jaw and a second jaw, at least one of the first and second jawsbeing movable toward the other of the first and second jaws forselective engagement of the cable; a second cable gripping devicecoupled to the frame to selectively engage and release the cable; a mainactuator to move the cable contacting portion in the non-linear range ofmotion and to actuate the second cable gripping device; a grippingactuator engaged to the cable contacting portion for actuating the firstcable gripping device; a first load spreading plate coupled to the frameto spread a portion of a pulling load against a first surface; and asecond load spreading plate coupled to the frame to spread a portion ofa pulling load against a second surface, wherein the first and secondload spreading plates are oriented generally perpendicularly to oneanother.
 17. The cable pulling device of claim 16, wherein the firstsurface is a side of a pit and the second surface is a bottom surface ofa pit, wherein the first and second load spreading plates act on theside and bottom surface of the pit, respectively, to resist a downwardtwisting force.
 18. The cable pulling device of claim 16, wherein thearcuate portion is elliptical.
 19. The cable pulling device of claim 16,wherein the main and gripping actuators are hydraulic cylinders.
 20. Thecable pulling device of claim 16, further comprising a connectionsurface for selective engagement with an implement arm.